When a car driver travelling at a speed of 20 m/s applies brakes and brings the car to rest in 40 s, then retardation will be :

A. + 2 m/s²

B. -2 m/s²

C. - 0.5 m/s²

D. + 0.5 m/s²

Which of the following statement is correct regarding velocity and speed of a moving body?

A. velocity of a moving body is always higher than its speed

B. speed of a moving body is always higher than its velocity

C. speed of a moving body is its velocity in a given direction

D. velocity of a moving body is its speed in a given direction.

Which of the following can sometimes be ‘zero’ for a moving body?

(i) average velocity

(ii) distance travelled

(iii) average speed

(iv) displacement

A. only (i) B. (i) and (ii)

C. (i) and (iv) D. only (iv)

Which of the following could not be a unit of speed?

A. km/h B. s/m

C. m/s D. mm s^-1

One of the following is not a vector quantity. This one is :

A. displacement B. speed

C. acceleration D. velocity